Heating and A/C System Options: Should I Change to a Different Type?
LESLIE: Tom in North Carolina, you’ve got The Money Pit. How can we help you today?
TOM IN NORTH CAROLINA: We have a house. It’s about – it was built in 2007. It’s about 2,700 square feet and we have two air conditioner/heat pump – you know, electric air conditioning/heat-pump units in it. And we’ve just been having headache after headache with trying to cool the house and heat the house with them.
We have a vaulted – kind of a vaulted ceiling, which looked great when we bought the house, and the registers are on the floor. But we’re constantly – the air conditioning and the heat units, they’re just running and running and running and running and running. They’re never really cooling down the house or heating down the house. The insulation is excellent at the house. I’m trying to figure out any alternatives – we do have a gas fireplace which, basically, just really doesn’t heat the house much but …
TOM: First of all, you’re saying that it doesn’t work in the cooling mode or the heating mode. Is that correct?
TOM IN NORTH CAROLINA: No, the cooling mode, it does work but – it cools the house down but it seems like the units run a lot. And I actually – to be quite honest with you, we did – we put some tinting stuff on some of the windows where they’re getting direct sunlight. But the heating side of it is just terrible. My kids are freezing on the second floor. We have a bonus room over the garage, which is pretty much insulated. We keep that door closed; it stays cool in there. And it just runs cold all the time.
And when I bring guys – people – out to look at it, they say, “The units run fine but you might want to put ductwork here, ductwork there, ductwork here.”
TOM: Well, I mean there may be some truth to that.
First of all, the fact of the matter is you need to understand that heating – heat-pump systems work different than a fossil-fuel system. A fossil-fuel system is going to warm air up and it’ll come out of the register at 125, 135 degrees.
A heat pump works different. A heat pump is going to throw air out at maybe 90 degrees. And so, very often, with a heat pump, you hear complaints of that, well, it blows cold air. Well, it doesn’t really blow cold air but the fact is that if you have a little moisture on your skin, you put your hand in front of it, that moisture evaporates and that makes it feel very chilly. And that’s one of the reasons it’s uncomfortable.
Then, of course, if it can’t keep up with demand, then it switches to its backup system, which is electric resistance heat. And of course, that’s really expensive to run. The heat-pump thermostat is designed to maintain a 2-degree temperature differential between what it is in the house and what you set it at. So if you set it at 72 degrees and it falls to 70 in the house, the heat pump will come on. If it falls to 69 or 68, the electric resistance heat will come on. Now, the air coming out of the ducts is going to be much warmer but you just more than doubled your expense.
Now, if the system is not doing its job, there’s a couple of things I would look at before I thought about replacing it, one of which is the duct design. Because if you’re not getting enough return air back to those units, then that could definitely be a contributing factor. You said that you’ve addressed the insulation part of it.
In terms of your thermostat, are you on a clock setback thermostat?
TOM IN NORTH CAROLINA: Yeah. And we have it – I mean it’s at 66 degrees in the wintertime. That’s what we have – it’s 66 and 67. We don’t have …
TOM: Maybe your kids are cold just because you haven’t turned the thermostat up.
TOM IN NORTH CAROLINA: Oh, we’re from up north, so we can deal with that. But what happens is when it starts running and running and running and running and running. It’s just like that’s all I keep hearing every 2 seconds: click-click, click-click, click-click, click-click, click-click.
But we have the option of propane. And being from up north, I lived with wood-burning stoves. And I grew up in Vermont and we had oil heat and electric backup for emergencies and stuff like that. But I’m just wondering if there’s anything on the propane side that might be more efficient.
TOM: Well, certainly, if you went to any kind of a fossil-fueled system, it’s going to put out warmer air. But I would want to make sure that the duct system was properly designed and installed before I do that.
Because if you change out your furnace and it turns out that the duct system isn’t installed properly or designed properly – if I was going to make a change, I would not want to just kind of get a seat-of-the-pants opinion by hiring an HVAC technician. I would want somebody who designs these systems for a living giving you a good, reasoned explanation as to what’s wrong with the system and why it needs to be fixed. I want you to guard against the handy-guy that comes out that maybe does most of the furnace service going, “Well, you could throw a duct in here, throw a duct in there.” That’s not what you want.
There’s a science behind this. It’s not a guess. You can figure out how many BTUs you need to heat a house, how many BTUs you need to cool a house. It’s called a heat-loss analysis or heat-loss calculation. And somebody that does this professionally can handle that.
So, I would take a look at the duct system first, see if it really is designed correctly. Because, frankly, many times it’s not. And then, based on that, decide if you want to change to a different type of heating system or perhaps even add supplemental heat on your own.
For example, you might decide that in that bonus room, where it’s cold all the time, that maybe some electric baseboard radiators in there would be a very inexpensive way to pick up just a little bit of heat – extra heat – when you need it, assuming it doesn’t need to be on all the time. It could be a low installation cost. Certainly a lot less than replacing your furnace and you could just have it when you want it.
But take a look at the duct design first. Nine out of ten times, that’s the source of this kind of issue as you’ve described it.
TOM IN NORTH CAROLINA: Thanks, guys.
TOM: You’re welcome, Tom. Good luck with that project.